Angles are measured in degrees (°). They can measure between 0° and 360°. Different types of angles include acute, obtuse, reflex and right angle. You can measure angles using a protractor.

If two 90 degree angles are placed back-to-back (Figure 5), they total 180 degrees. The sides of this angle form a straight line, so a 180 degree angle is a straight line. Adding two more 90 degree ...

An acute angle is less than 90°. An obtuse angle is between 90° and 180°. A reflex angle is between 180° and 360°. The size of an angle can be estimated without using a protractor.